2) H.F. Mark, D.F. Othmer, C.G. Overberger, G.T. Seaborg, and Kirk-Othmer“Encydopedia of Chemical Technology”, 3rd Edition, Vol. 17, Wiley, New York (1982), p.384
3) A. Knop and W. Scheib, “Chemistry and Application of Phenolic Resins”, Springer, New York (1979).